CN114592283B

CN114592283B - Preparation method of nanofiber membrane based on controlled-release embedded flavor substances

Info

Publication number: CN114592283B
Application number: CN202210158051.1A
Authority: CN
Inventors: 黄章琪; 邹小波
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2023-05-09
Anticipated expiration: 2042-02-21
Also published as: CN114592283A

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of a controlled-release embedded flavor substance nanofiber membrane. Firstly, adding a polyvinyl alcohol solution into a chitosan solution, then dropwise adding a synergistic flavor substance, and obtaining a shell layer solution after sealing, stirring and dissolving; the mass concentration of the synergistic flavor-developing substance in the shell solution is 0.5-1.5 g/100mL; mixing zein solution with gelatin solution, and adding flavoring substances to obtain core layer solution; the concentration of the flavor substances in the nuclear layer solution is 12-15 g/100mL; finally, a nanofiber membrane is obtained by a coaxial electrostatic spinning technology through a shell layer solution and a core layer solution; the nanofiber membrane contains 0.006-0.0075 g of flavor substances per unit square centimeter. The invention provides an edible nanofiber membrane capable of accurately controlling and releasing flavor substances in unit area, which solves the problems of uneven distribution of embedding substances and poor taste.

Description

Preparation method of nanofiber membrane based on controlled-release embedded flavor substances

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of a controlled-release embedded flavor substance nanofiber membrane.

Background

Flavoring means a compound that improves the mouthfeel of a food product and imparts a characteristic flavor and odor to the food product. Whereas taste sensation is the sensation of food produced by the stimulation of a taste organ within a person's mouth. Generally include psychological taste (shape, color), physical taste (temperature, hardness, mouthfeel, etc.), chemical taste (sour, sweet, bitter, spicy, salty, fresh, spicy, astringent). The traditional Chinese people have the characteristics of heavy salt, sweet taste and fresh taste in vegetable making and eating habits. The actual intake of common salt according to the daily investigation of Chinese residents is about 12g, which is far more than the standard of the world health organization; and the daily intake of sugar is far more than the recommended daily intake of 25 g. Such dietary structures have long resulted in significant physical injury such as hypertension, gastric cancer, osteoporosis, obesity, asthma, kidney disease, and the like. So the society now proposes low sugar and low salt, light eating habits, which can reduce the risk of diseases and enhance the resistance of human body to influenza. However, it has become an urgent problem at the present stage how to reduce the addition amount of the flavoring substances without reducing the taste. At present, no specific taste-reducing processing operation exists in food processing, and the adding amount of salt is generally reduced to the greatest extent by calculating the material dosage required by a unit area, but the problem of taste-developing material accumulation and uneven distribution is easily caused by external addition, and the taste and the adding amount are also influenced, so a method for realizing uniform distribution of materials by embedding the flavor materials is proposed to solve the problem.

The embedding method is a method of embedding a substance in a fine gel network of a polymer or in a semipermeable polymer membrane. Similarly, the embedding can uniformly encapsulate the flavoring substances in the wall material, and the embedding can accurately calculate the embedding amount of the target substances, so that the purposes of low content and uniform distribution of the flavoring substances are realized. Typical embedding methods for referring to the current flavor substances, specific embedding techniques for flavor substances, are gel embedding, spray drying and microcapsule embedding. The application number is as follows: CN201510026208.5 prebiotics low sodium salt and a preparation method thereof, and powdered prebiotics are directly added into the low sodium salt by a spray drying method. Application number: 202010566001.8; a method for preparing microcapsule-embedded kelp polyphenol biscuit and its product are provided. However, the existing embedding method has various problems, such as incapability of realizing food safety, incapability of uniformly distributing embedded substances in an embedding material, and uneven flavor distribution and poor taste.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to solve the technical problem that the adding amount of flavor substances in food exceeds the standard, namely, the accurate control of the intake of the flavor substances by consumers under the condition of meeting the taste of the food is difficult to realize, thereby providing the preparation method of the edible nanofiber membrane capable of accurately controlling the release of the flavor substances in unit area.

In order to achieve the above object, the present invention is embodied as follows:

step one: preparing spinning solution;

(1) Preparation of a shell solution: firstly, taking polyvinyl alcohol, wherein the molecular weight of the polyvinyl alcohol is 85000-124000, and the hydrolysis degree is 95-99%; adding polyvinyl alcohol into water to obtain a polyvinyl alcohol solution; then taking chitosan with the viscosity of 100-200 mPa.s and the deacetylation degree of 95-99%; mixing chitosan with acetic acid aqueous solution to obtain chitosan solution;

finally, mixing the polyvinyl alcohol solution and the chitosan solution, dropwise adding the synergistic flavor-developing substance after stirring, and sealing and stirring after dropwise adding, wherein the mixed solution obtained after dissolving is the shell layer solution; the mass concentration of the synergistic flavor-developing substance in the shell layer solution is 0.5g/100 mL-1.5 g/100mL;

(2) Preparation of core layer solution: firstly, taking zein with the molecular weight of 25000-29000, dissolving the zein in ethanol solution, and fully stirring the zein solution; then dissolving gelatin in deionized water to obtain gelatin solution; finally, mixing and stirring the zein solution and the gelatin solution according to a proportion, adding the flavor substances, and uniformly stirring to obtain a nuclear layer solution; the concentration of the flavor substance in the nuclear layer solution is 12g/100 mL-15 g/100mL;

step two: preparing a nanofiber membrane;

and (3) setting spinning conditions, namely, using the shell layer solution and the core layer solution prepared in the step (I), adopting an electrostatic spinning technology of coaxial electrospinning, and using tinfoil paper as a receiving material, wherein the inner spinning and the outer spinning are performed through superposition, and a nanofiber membrane is obtained by rotating a roller on a collector, namely, the nanofiber membrane based on the controlled-release embedded flavor substances, and each unit square centimeter of the nanofiber membrane contains 0.006-0.0075 g of the flavor substances.

Preferably, in the step (1), the mass concentration of the polyvinyl alcohol aqueous solution is 8-12%.

Preferably, in the step (1), the mass concentration of the chitosan solution is 4%; the volume ratio of acetic acid to water in the aqueous acetic acid solution is 8:2, and the acetic acid used belongs to the analytical grade.

Preferably, in the step (1), the volume ratio of the polyvinyl alcohol solution to the chitosan solution is 2-8:2-8; more preferably in a ratio of 4:6.

Preferably, in the step (1), the synergistic taste-developing substance is salty, sweet, spicy, sour or umami edible material; specifically includes mushroom alcohol (salty taste) or stevioside (sweet taste).

Preferably, in the step (2), the mass concentration of the zein solution is 20-25%, and the volume fraction of the ethanol solution is 80%; the mass concentration of the gelatin solution is 0.3-0.5%; the volume ratio of the zein solution to the gelatin solution is 3-5: 1, a step of; more preferably in a ratio of 3:1.

Preferably, in the step (2), the flavoring substance is salty, sweet, spicy, sour or umami edible material; specifically, the food comprises salt (salty), stevioside (sweet) or pepper (spicy).

Preferably, in the second step, the spinning conditions of the electrospinning are as follows: the voltage is 17-20 kv, the receiving distance is 10-14 cm, the pushing rate of the shell layer solution is 1.0-4.0 mL/h, the pushing rate of the core layer solution is 0.1-0.3 mL/h, the spinning temperature is 40-45 ℃, the relative humidity is maintained at 20-25%, and the speed of the rolling shaft is 30-80 r/min.

The invention adopts the electrostatic spinning technology of coaxial electrospinning, which is also a proposal method for obtaining a nanoscale fiber membrane, and generates a typical shell-core structure, wherein the shell layer is a synergistic flavor fiber layer, and the core layer is a flavor substance release layer; the flavor substances can be uniformly distributed in the wall material through the condition parameters of accurate spinning, and the fiber with uniform thickness is obtained, so that a powerful mechanical structure and good physical properties are provided for quantitatively reducing the content of the flavor substances and the controlled release in the later period.

The invention has the beneficial effects that:

compared with the traditional film, the nanometer-scale fiber is obtained by the film forming technology of electrostatic spinning, the special-shaped film has larger specific surface area, can wrap the flavor substances in the fiber, and ensures that the flavor substances are uniformly distributed in the fiber film in small particles, so that the film has higher flavor taste and lower concentration flavor substance distribution in the same unit, and simultaneously, the contact area of the flavor substances in the fiber film and foods is also improved.

The film forming materials related by the invention are all safe and nontoxic, and have food safety, such as chitosan, gelatin and synergistic flavor substances. The solvent is volatilized during the electrostatic spinning process, but the components of the solvent are water and acetic acid which are safe and nontoxic and safe to eat. Through the spinning technology of electrostatic spinning and proper solution proportion, the content of the flavor substances in unit area can reach the minimum value under the condition of meeting the taste. The flavor substance takes salt as an example, the mushroom alcohol in the film-forming material is used as a synergistic flavor substance, so that the salt content in unit area can be further reduced, the effects of salt reduction and flavor enhancement are realized, and experiments prove that the flavor of the mushroom alcohol in the electrospun fiber is embedded, but the flavor of the mushroom alcohol is recovered at the moment that the wall material is broken and swelled, and the mushroom alcohol and the salty taste have a synergistic effect, so that the overall sensory quality of food is further improved.

Most important is the proportion of the spinning solution to be prepared and the addition of the flavor substances; in a shell layer solution, experimental data show that the proportion of a polyvinyl alcohol solution (PVA) and a Chitosan Solution (CS) is respectively prepared according to the proportions of 2:8,3:7,4:6,5:5,6:4,7:3 and 8:2, and the obtained spinning is subjected to SEM to see microscopic morphology of fibers under an electron microscope, wherein the average diameter of the fibers is 730nm at PVA: CS=4:6, the surface of the obtained film obtained by spinning is smooth and flat and is easy to peel, the proportion is critical, when the PVA quality is too high, the diameter of the fibers is smaller but the fibers are easy to break, and a stacking area with nonuniform color is formed on the surface of the nanofiber membrane obtained by spinning. However, when the PVA mass ratio is too low and CS is dominant, the fiber diameter is large and the surface thereof is rough and uneven, and the surface of the nanofiber membrane obtained by spinning is uneven. Similarly, the proportion of zein solution (ZN) and gelatin solution (GA) in the core layer solution needs to be precisely controlled, the ZN mass ratio is too high, the taste of the film is sweet, the ZN mass ratio is too low, the fiber diameter is small and the fiber is broken, and therefore the surface flatness of the nanofiber film is affected. On the other hand, in the addition amount of the flavor substance, in order to accurately amount the flavor substance per unit square centimeter area; on the basis of precisely controlling the proportion of the spinning solution, the number of spinning in unit area and the upper limit value of the content of the additive can be determined; so, calculation and experiments prove that 10mL of nanofiber membrane is spun, and 12% -15% of flavor additive is needed, so that 0.006-0.0075 g of additive in unit square centimeter is obtained.

Drawings

FIG. 1 is a schematic illustration of a spinning process using the coaxial electrospinning technique of the present invention; wherein 1-a shell solution; 2-shell syringe; 3-a secondary mechanical pump; 4-nuclear layer solution; a 5-nuclear layer syringe; 6-a main mechanical pump; 7-nuclear layer solution at the needle junction; 8-a sheath solution at the needle junction; 9-a needle; 10-flavoring substances; 11-core layer fiber; 12-shell fiber; 13-microstructure of the fibers; 14-collecting plate; 15-high voltage power supply.

FIG. 2 is a schematic representation of the flavor diffusion of the present invention; wherein 1-shell fiber; 2-core layer fibers; 3-flavor particles.

FIG. 3 is an electron microscopic scan of the nanofiber membrane according to the invention obtained in examples 1-6; wherein a is figure-example 1; b diagram-example 2; c diagram-example 3; FIG. D-example 4; FIG. E-example 5; f Panel-example 6.

FIG. 4 is a graph showing the release efficiency of a flavor substance (for example, common salt) of the nanofiber membrane obtained in example 2 and comparative example 1 of the present invention.

FIG. 5A is a graph showing the sensory evaluation results and the salt content per unit area of the nanofiber membrane under different salt contents; the B graph is a graph of the sensory evaluation result of directly adding the salt amount corresponding to the A graph on the surface of the boiled rice; and C, the diagram is a diagram of the sensory evaluation result of directly adding the salt on the surface of the rice after increasing the salt content.

FIG. 6 is a graph showing the effect of releasing concentration of flavor substances (salt is taken as an example) of a shell layer solution and a core layer solution according to different ratios; wherein the core layer contains 15% of salt and the shell layer contains 1.5% of mushroom alcohol; b-core layer containing 15% Sal and shell layer containing 1% mushroom alcohol; the C-core layer contains 15% salt and the shell layer contains 0.5% mushroom alcohol; the D-core layer contains 12% of salt and the shell layer contains 1% of mushroom alcohol; the E-core layer contains 12% Sal and the shell layer contains 1.5% mushroom alcohol.

The specific embodiment is as follows:

the present invention will be further described in detail with reference to specific embodiments and drawings for the purpose of making the objects, technical solutions and advantages of the present invention more apparent.

Example 1:

the preparation method of the nanofiber membrane based on the controlled release embedded salty substances adopts a coaxial electrostatic spinning technology and comprises the following steps:

step one: preparation of spinning solution

(1) Preparing a shell layer solution; firstly, selecting polyvinyl alcohol with molecular weight of 85,000 ～ 124,000 and degree of hydrolysis of 95% -99%, and adding the polyvinyl alcohol into water to obtain a polyvinyl alcohol solution with mass concentration of 12%;

then taking chitosan, wherein the viscosity is 100-200 mPa.s, and the deacetylation degree is 95-99%; dissolving chitosan by using an acetic acid aqueous solution to obtain a chitosan solution with the mass concentration of 4%, wherein the volume ratio of acetic acid to water is 8:2;

mixing a polyvinyl alcohol solution with a chitosan solution according to a volume ratio of 4:6, adding mushroom alcohol after fully stirring, sealing and stirring, and dissolving to obtain a shell solution; the concentration of the mushroom alcohol in the shell solution is 1.5g/100mL;

(2) Preparing a nuclear layer solution; firstly, zein (the molecular weight of which is 25,000 ～ 29,000) is selected to be dissolved by ethanol solution with the volume fraction of 80 percent, and the zein solution with the mass concentration of 22 percent is obtained after full stirring; and then dissolving gelatin into deionized water to obtain gelatin solution with mass fraction of 0.3%.

Mixing and stirring zein solution with gelatin solution according to the volume ratio of 3:1 in a water bath kettle at 45 ℃, and then adding salt and uniformly stirring to obtain a core layer solution, wherein the concentration of the salt is 15g/100mL.

Step two: preparation of nanofiber membranes

Respectively sucking 5mL of the prepared shell layer solution and core layer solution by two syringes, placing the two syringes on a coaxial line, adopting the electrostatic spinning technology of coaxial electrospinning, taking tinfoil paper as a receiving material, and rotating a roller on a collector to obtain a nanofiber membrane; wherein the spinning conditions are as follows: the voltage is 20kv, the receiving distance is 10cm, the pushing rate of the shell layer solution is 1.0mL/h, the pushing rate of the core layer solution is 0.1mL/h, the spinning temperature is 40 ℃, the relative humidity is maintained at 23%, and the speed of the rolling shaft is 30r/min.

The invention adopts the electrostatic spinning technology of coaxial electrospinning, and is also a suggested method for obtaining a nanoscale fiber membrane, and a typical shell-core structure is generated, wherein the shell layer is a synergistic flavor fiber layer, and the core layer is a salty substance release layer.

Example 2:

step one: preparation of spinning solution

mixing a polyvinyl alcohol solution with a chitosan solution according to a volume ratio of 4:6, adding mushroom alcohol after fully stirring, sealing and stirring, and dissolving to obtain a shell solution; the concentration of the mushroom alcohol in the shell solution is 1g/100mL;

Step two: preparation of nanofiber membranes

Example 3:

step one: preparation of spinning solution

mixing a polyvinyl alcohol solution with a chitosan solution according to a volume ratio of 4:6, adding mushroom alcohol after fully stirring, sealing and stirring, and dissolving to obtain a shell solution; the concentration of the mushroom alcohol in the shell solution is 0.5g/100mL;

Step two: preparation of nanofiber membranes

Example 4:

step one: preparation of spinning solution

Mixing and stirring zein solution with gelatin solution according to the volume ratio of 3:1 in a water bath kettle at 45 ℃, and then adding salt and uniformly stirring to obtain a core layer solution, wherein the concentration of the salt is 12g/100mL.

Step two: preparation of nanofiber membranes

Example 5:

step one: preparation of spinning solution

Step two: preparation of nanofiber membranes

Example 6:

the preparation method of the nanofiber membrane based on the controlled release embedded sweet substance adopts a coaxial electrostatic spinning technology and comprises the following steps:

step one: preparation of spinning solution

(1) Preparing a shell layer solution; firstly, selecting polyvinyl alcohol with molecular weight of 85,000 ～ 124,000 and degree of hydrolysis of 95% -99%, and adding the polyvinyl alcohol into water to obtain a polyvinyl alcohol solution with mass concentration of 10%;

mixing a polyvinyl alcohol solution with a chitosan solution according to a volume ratio of 4:6, adding stevioside after fully stirring, sealing and stirring, and dissolving to obtain a shell solution; the concentration of stevioside in the shell solution is 0.5g/100mL;

(2) Preparing a nuclear layer solution; firstly, zein (the molecular weight of which is 25,000 ～ 29,000) is selected to be dissolved by ethanol solution with the volume fraction of 80 percent, and the zein solution with the mass concentration of 20 percent is obtained after full stirring; and then dissolving gelatin into deionized water to obtain gelatin solution with mass fraction of 0.3%.

Mixing and stirring zein solution according to the volume ratio of gelatin solution of 3:1 in a water bath kettle at 45 ℃, and then adding sucrose and uniformly stirring to obtain a nuclear layer solution, wherein the concentration of the sucrose is 10g/100mL.

Step two: preparation of nanofiber membranes

The invention adopts the electrostatic spinning technology of coaxial electrospinning, and is also a suggested method for obtaining a nanoscale fiber membrane, and a typical shell-core structure is generated, wherein the shell layer is a synergistic flavor fiber layer, and the core layer is a sweet substance release layer.

A nanofiber membrane structure as shown in fig. 3, wherein a is shown in fig. 1; b diagram-example 2; c diagram-example 3; FIG. D-example 4; FIG. E-example 5; f chart-example 6, the flavor substances can be uniformly distributed in the coating material by the condition parameters of accurate spinning, and the fiber with uniform thickness is obtained, which provides powerful mechanical structure and good physical property for quantitatively reducing the salt content and controlling release in the later period.

Comparative example 1:

the preparation method of the nanofiber membrane based on the controlled release embedded salty substances adopts a uniaxial electrostatic spinning technology and comprises the following steps:

step one: preparation of spinning solution

Preparing a spinning solution; firstly, zein (the molecular weight of which is 25,000 ～ 29,000) is selected to be dissolved by ethanol solution with the volume fraction of 80 percent, and the zein solution with the mass concentration of 22 percent is obtained after full stirring; and similarly, dissolving gelatin into deionized water to obtain gelatin solution with mass fraction of 0.3%.

Mixing zein solution with gelatin solution according to a volume ratio of 3:1, mixing and stirring in a water bath kettle at 45 ℃, adding salt, and stirring and dissolving to obtain spinning solution, wherein the concentration of the salt is 15g/100mL;

step two: preparation of nanofiber membranes

Sucking 10mL of the prepared spinning solution by using a syringe, and placing the solution on a spinning instrument to prepare for spinning; taking tinfoil paper as a receiving material, and rotating a roller on a collector to obtain a nanofiber membrane; wherein the spinning conditions are as follows: the voltage is 20kv, the receiving distance is 10cm, the pushing rate of the shell layer solution is 1.0mL/h, the pushing rate of the core layer solution is 0.1mL/h, the spinning temperature is 40 ℃, the relative humidity is maintained at 23%, and the speed of the rolling shaft is 30r/min.

The current electrostatic spinning technology of uniaxial electrospinning is adopted, and only a single-layer fiber film with embedded flavor substances can be generated.

Performance test 1: and comparing the flavor substance release conditions of the nanofiber membrane obtained by uniaxial spinning and coaxial spinning in the oral simulation process.

The testing steps are as follows: the nanofiber membrane material was cut into 2 x 2cm squares and placed in 10mL of aqueous solution at intervals of 2 minutes, and the concentration of NaCl in the solution was measured once, thereby drawing a release profile.

Taking comparative example 1 as a control group, dividing the prepared nanofiber membrane into 2 groups, stirring and grinding one group by a glass rod in the process of soaking in aqueous solution, and simulating the process of chewing the oral cavity (marked as group A); the other group was not subjected to stirring and grinding operations (noted as group C).

The nanofiber membrane obtained in example 2 was used as an experimental group, and was also divided into 2 groups, one group was stirred and ground with a glass rod during the soaking in its aqueous solution, and the process of chewing the mouth was simulated (denoted as group B); the other group was not subjected to stirring and grinding operations (noted as group D).

As a result, as shown in FIG. 4, the nanofiber membrane prepared by uniaxial spinning was free from stirring and grinding, and the wall material was hydrophilic, so that swelling and rupture of the wall material after water absorption occurred to release the flavor substance. However, since the outer hydrophobic shell layer is spun coaxially, the release rate is less than 5% without stirring and grinding, i.e. the flavor of the core layer is hardly released (grinding and stirring simulate the chewing process of the oral cavity). From the above, it is found that coaxial spinning has better properties in terms of both the controlled release effect and the preservability of spinning than uniaxial spinning.

Performance test 2: comparing edible sensory evaluation conditions of different salt contents, and selecting a better sensory addition amount. And simultaneously comparing the sensory eating condition of directly adding salt and embedding the salt by using a fiber membrane.

The testing steps are as follows: the first experiment (group a) was performed by dividing nanofiber membranes with different salt addition amounts (only the salt addition amount was changed according to the operation method of example 2) into 6 groups: the concentration (mg/ml) of the salt is 8% in sequence; 10%;12%;15%;17%;20%. Cutting the nanofiber membrane into square with the length of 2 multiplied by 2cm, and stacking 5 layers of nanofiber membranes with the same concentration on 20g of boiled rice; wait for sensory panelists to score the ratings.

The second group (group B) was to add different amounts of table salt directly onto the white rice (20 g), divided into 6 groups: the salt consumption is 0.32g in sequence; 0.40g;0.48g;0.6g;0.68g;0.80g (the six groups of experiments added the same amount of salt as the first group of nanofiber membranes); wait for sensory panelists to score the ratings.

A third experiment (group C) was designed to add different amounts of table salt directly to the white rice (20 g) and divided into 6 groups: the salt consumption is 0.65g in sequence; 0.8g;0.95g;1.05g;1.2g;1.35g (this group is to find out what the better added amount of directly added salt taste is, it is convenient to compare with the optimal taste added amount in the fiber film); wait for sensory panelists to score the ratings.

Sensory evaluation: 50 food professional students with professional training are invited to form a sensory evaluation group, the score is adopted to be quite made, each sample is evaluated 3 times, and the calculation result is averaged. Evaluation criteria, score 0-3: poor taste and uneven salty taste; 4-6 minutes: the taste is good, and the salty taste is relatively uniform; 7-10 tastes good, the salty taste is evenly distributed, and 50 parts of sensory evaluation results are finally collected.

The results are shown in FIG. 5, wherein A is the sensory evaluation of the different salt addition concentrations (8% -20%) and the variation of the salt content per unit area. It was found that a better sensory experience was achieved between 6.20.+ -. 0.88 and 7.40.+ -. 0.81 for sensory evaluation results with a salt content between 12% and 17%. And the salt content per unit area of the interval is 0.006-0.0085g/cm ² Between them. The B graph and the C graph are sensory evaluation and respective change values of salt content per unit area, wherein the sensory evaluation and the change values of salt content per unit area are obtained by directly adding the salt according to different addition concentrations (the B graph is to compare the A graph to add the same amount of salt of 0.32g-0.8g/20g of rice; the C graph is to continue to add the salt content to find the salt content and the A graph reaches the same salt addition amount of taste). It was found that a better sensory experience was achieved between 5.80.+ -. 0.88 and 6.40.+ -. 0.78 in the sensory evaluation results between 0.8-1.05g salt content per 20g rice. The overall trend of the results is the same as that of the graph A, but the salt content required for achieving the same sensory feeling is higher (for example, the NaCl accounts for 15% in the graph A, and the best sensory evaluation result in the group is obtained by rice with NaCl of 0.95g/20g in the graph C), which reflects the problems that the direct addition of salt is easy to cause uneven diffusion and easy to agglomerate, and finally the problem of high salt intake is caused; therefore, the method can really meet the consumption requirements of salt reduction and no odor reduction.

Performance test 3: comparing the release conditions of the flavor substances of the shell layer solution and the core layer solution with different proportions, and searching the optimal flavor substance addition amount.

The testing steps are as follows: the nanofiber membrane was cut into a square of 2×2cm, placed in 10mL of aqueous solution at every 2 minutes, and the concentration of NaCl in the solution was measured once, thereby drawing a release profile.

According to the results of the performance test 2, in the optimal salt addition interval, the salt addition amounts of 12% and 15% are selected, and based on the salt addition amounts, the salt addition amounts are divided into 5 groups, namely A groups respectively: the core layer contains 15% salt + the shell layer contains 1.5% mushroom alcohol (example 1); group B: the core layer contains 15% salt + the shell layer contains 1% mushroom alcohol (example 2); group C: the core layer contained 15% salt + the shell layer contained 0.5% mushroom alcohol (example 3); group D: the core layer contains 12% salt + the shell layer contains 1% mushroom alcohol (example 4); group E: the core layer contained 12% salt + the shell layer contained 1.5% mushroom alcohol (example 5).

As shown in fig. 6, the results are shown as release effect graphs under different concentrations, and the nanofiber membranes prepared under the five concentration conditions are subjected to sensory evaluation, so that the group B and the group C simultaneously meet the better sensory experience and the ratio of theoretical release time, namely, reach the preset taste concentration within 8 to 10 seconds.

Description: the above embodiments are only for illustrating the present invention and not for limiting the technical solution described in the present invention; thus, although the present invention has been described in detail with reference to the above embodiments, it will be understood by those skilled in the art that the present invention may be modified or equivalent; all technical solutions and modifications thereof that do not depart from the spirit and scope of the present invention are intended to be covered by the claims of the present invention.

Claims

1. The preparation method of the nanofiber membrane based on the controlled-release embedded flavor substance is characterized by comprising the following steps:

step one: preparing spinning solution;

(1) Preparation of a shell solution: firstly, taking polyvinyl alcohol, wherein the molecular weight of the polyvinyl alcohol is 85000-124000, and the hydrolysis degree is 95% -99%; adding polyvinyl alcohol into water to obtain a polyvinyl alcohol solution; then taking chitosan, wherein the viscosity of the chitosan is 100-200 mPa.s, and the deacetylation degree is 95% -99%; mixing chitosan with acetic acid aqueous solution to obtain chitosan solution;

finally, mixing the polyvinyl alcohol solution and the chitosan solution, dropwise adding the synergistic flavor-developing substance after stirring, and sealing and stirring after dropwise adding, wherein the mixed solution obtained after dissolving is the shell layer solution; the mass concentration of the synergistic flavor-developing substance in the shell layer solution is 0.5g/100 mL-1.5 g/100mL; the mass concentration of the polyvinyl alcohol solution is 8-12%, and the mass concentration of the chitosan solution is 4%; the volume ratio of the polyvinyl alcohol solution to the chitosan solution is 4:6;

(2) Preparation of core layer solution: firstly, taking zein with the molecular weight of 25000-29000, dissolving the zein in ethanol solution, and fully stirring to obtain zein solution; then dissolving gelatin in deionized water to obtain gelatin solution; finally, mixing and stirring the zein solution and the gelatin solution according to a proportion, adding flavor substances, and stirring to obtain a nuclear layer solution; the concentration of the flavor substances in the nuclear layer solution is 12g/100 mL-15 g/100mL;

step two: preparing a nanofiber membrane;

and (3) setting spinning conditions, namely, using the shell layer solution and the core layer solution prepared in the step (I), adopting an electrostatic spinning technology of coaxial electrospinning, using tinfoil paper as a receiving material, performing inner spinning and outer spinning through superposition, and rotating a roller on a collector to obtain a nanofiber membrane, namely, the nanofiber membrane based on the controlled-release embedded flavor substances, wherein each unit square centimeter of the nanofiber membrane contains 0.006-0.0075 g of the flavor substances.

2. The method of claim 1, wherein in step (1), the volume ratio of acetic acid to water in the aqueous acetic acid solution is 8:2.

3. The method of claim 1, wherein in step (1), the synergistic flavor-imparting substance is salty, sweet, spicy, sour, or umami edible material.

4. A method of preparing a controlled release embedded flavor nanofiber membrane according to claim 3, wherein in step (1), the synergistic flavor is mushroom alcohol or stevioside.

5. The method for preparing a controlled release embedded flavor substance-based nanofiber membrane according to claim 1, wherein in the step (2), the mass concentration of the zein solution is 20-25%, and the volume fraction of the ethanol solution is 80%; the mass concentration of the gelatin solution is 0.3-0.5%; the volume ratio of the zein solution to the gelatin solution is 3-5: 1.

6. the method of claim 5, wherein the zein solution is mixed with the gelatin solution in a volume ratio of 3:1.

7. The method of claim 1, wherein in step (2), the flavor is salty, sweet, spicy, sour, or umami edible material.

8. The method for preparing a nanofiber membrane based on a controlled release embedded flavor substance according to claim 7, wherein the flavor substance specifically comprises table salt, stevioside or capsicum.

9. The method for preparing a nanofiber membrane based on a controlled release embedded flavor substance according to claim 1, wherein in the second step, the spinning conditions of the electrospinning are as follows: the voltage is 17-20 kv, the receiving distance is 10-14 cm, the pushing rate of the shell layer solution is 1.0-4.0 mL/h, the pushing rate of the core layer solution is 0.1-0.3 mL/h, the spinning temperature is 40-45 ℃, the relative humidity is maintained at 20-25%, and the speed of the rolling shaft is 30-80 r/min.